(1 同济大学地下建筑与工程系， 上海 200092； 2 华东建筑设计研究院有限公司地下空间与工程设计研究院， 上海 200002)

［摘要］静钻根植桩是一种绿色环保的新型桩基，以往研究工作较少关注静钻根植桩桩身质量及形态，而这是正确认识这类桩基性能的基础。以上海彩虹湾医院项目为依托，基于静载试验、现场开挖验证、水泥土无侧限抗压强度试验和静力触探测试，较系统地分析了上海地区静钻根植桩成桩效果与质量。研究结果表明，静钻根植桩适用于上海地区地层条件，施工效率较高，具有可靠的竖向抗压和抗拔承载力；开挖范围内桩身基本呈圆柱形，水泥土和预制桩胶结良好；桩身水泥土搅拌较均匀，沿深度水泥土强度较稳定。研究成果可为上海地区静钻根植桩实践与理论研究提供参考。

［关键词］静钻根植桩； 静载试验； 水泥土； 成桩效果； 施工工效

中图分类号：TU473-1文献标识码：A文章编号：1002-848X(2019)12-0115-05

Experimental study on pile-forming effect and quality of pre-bored precast pile with enlarged base in Shanghai area

Wang Weidong1,2, Ling Zao1, Wu Jiangbin2, Yuan Juyun1

(1 Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China; 2 Underground Space & Engineering Design & Research Institute， East China Architecture Design & Research Institute Co., Ltd., Shanghai 200002, China)

Abstract:The pre-bored precast pile with enlarged base (PPEB pile) is an innovative type of environmental pile foundation. In the past, little attention has been paid to the quality and shape of the PPEB piles, which is the basis for the accurate understanding of the performance of such piles. Based on static load tests, site excavation validation, unconfined compression tests and cone penetration tests in Shanghai Rainbow Bay Hospital, pile-forming effect and quality of PPEB piles in Shanghai area were analyzed. The test results show that the PPEB pile is suitable for the stratum condition in Shanghai area, with high construction efficiency and reliable vertical compressive and uplift bearing capacity. In the excavation area, the shape of the pile shaft is nearly cylindrical, cemented soil and inner precast piles are well cemented. The cement-soil mixing of pile shaft is uniform,  the strength of cement-soil is stable along the depth. The test results provide guidance  for the practice and theoretical research of PPEB pile in Shanghai area.

Keywords:pre-bored precast pile with enlarged base; static loading test; cement soil; pile-forming effect; construction efficiency

*上海市优秀学术/技术带头人计划(18XD1422600)。

作者简介：王卫东，博士，教授级高级工程师，博士生导师，Email：weidong_wang@ecadi.com。